The present invention relates to an improved apparatus and method for removing liquid from a container, and in particular to an apparatus and method for dispensing chemicals, such as liquid chemicals for use in commercial laundry systems, from a plurality of containers, whereby substantially all of the liquid in the containers is withdrawn during dispensing.
Liquids may be provided to the end user in several different types of containers, holding from one gallon or less up to about 55 gallons. Some of these containers are of blow molded plastic and have a circular bottom wall, a continuous side wall extending upwardly from the periphery of the bottom wall, and an upper wall including a mouth or opening for removal of the liquid. With smaller containers holding up to 5 gallons, the side wall may taper inwardly at its upper end to form an upper wall with a centrally located mouth. The mouth is normally covered by a screw cap that is removed when the container is positioned for dispensing. Other blow molded containers holding up to 2 gallons may have a rectangular or oval shape, such as the shape of a conventional antifreeze container.
Small quantities, e.g., up to 5 gallons, of liquid chemicals are also packaged in bag-in-box containers comprised of a cardboard box enclosing a flexible, blow molded, plastic liner. The liner includes a mouth or opening that protrudes from an opening in the top of the box when liquid is to be dispensed, and is recessed into the box during shipping. The box opening may be offset, i.e., located closer to one side wall than the other side walls, to facilitate pouring.
In operating commercial laundry machines, containers filled with liquid laundry chemicals, e.g. detergents, fabric softeners, bleach, etc., are placed in the vicinity of the washing machines, and liquids are pumped from the various containers in response to signals from the washing machines. Normally, chemicals are removed by placing the containers on a horizontal surface and inserting a rigid tube or probe into the mouth of the container by hand. The probe will usually be positioned in a random manner. Often, the probe will extend substantially vertically down into the container. Since the bottom wall of most detergent containers is concave to ensure that the container rests firmly on the surface, a probe inserted vertically into the container will rest on the upper surface of the central concave portion of the bottom wall. As a result, the liquid at the juncture of the side and bottom walls of the container, i.e., the lowest part of the container interior, will not be accessible to the probe.
Even if the probe is inserted at an angle into the container, it may not be long enough to extend completely to the juncture of the side and bottom walls, or the distal end of the probe will be of a configuration such that all of the liquid will not be removed. Conventionally, the ends of probes are cut at an angle. Thus, when the liquid level is lowered to the top of the probe opening, air is drawn into the probe, leaving a portion of the liquid still within the container.
U.S. Pat. No. 5,238,146 to Thome, Jr., describes a technique for reducing the amount of liquid left in drams by tilting the drams with an insert to be placed under one edge of the dram. A probe or suction tube is then inserted vertically through an opening in the top of the dram so that the lower end of the probe is adjacent the juncture of the bottom and side walls of the dram, permitting removal of a greater portion of the liquid. Since the probe is inserted into the dram by hand, there is no assurance that the lower end of the probe will engage the lowermost portion of the drum interior. Moreover, the probe may shift during pumping. Even if the end of the probe happens to extend all the way in the lowermost portion of the dram, all of the liquid will not be removed since the end configuration of the probe will permit the entry of air into the probe before complete removal of the liquid.
Thus, in prior procedures, removal of liquid from containers using a probe or suction tube has resulted in a small amount of liquid remaining in the container. While the quantity of liquid left in a single container is small, the cumulative volume can be quite significant, when considering the large number of containers used to dispense chemicals in the laundry industry. In addition to the cost resulting from the loss of these chemicals, disposal of containers containing the chemicals into landfills and the like is environmentally undesirable and potentially hazardous to workers engaged in disposal of the containers.
Therefore, there is a need for an apparatus and method for ensuring substantially complete emptying of containers of liquids in which the liquids are removed from the containers with a probe or suction tube. There is especially a need for an apparatus of this type for automated removal of chemicals from a plurality of containers in dispensing of chemicals to commercial laundry machines. Other aspects of the invention will be apparent to one skilled in the art upon the reading of the following summary of the invention and the derailed description of the preferred embodiment.